1. Field of the Invention
The invention relates to a new form of ZSM-4, to a process for preparing it and to a method for using it in hydrocarbon conversion reactions. More particularly, it relates to making and using ZSM-4 which, in its synthesized form, has a different nitrogen-containing cation, but the same crystal structure as previously synthesized ZSM-4.
2. Summary of the Prior Art
ZSM-4 is a relatively new zeolite which in its previously synthesized aluminosilicate form has the following composition expressed in terms of mole ratios of oxides: EQU 0.9 .+-. 0.2 M.sub.2 O : Al.sub.2 O.sub.3 : 3-20 SiO.sub.2 : 0-20 H.sub.2 O
wherein M is selected from the group consisting of a mixture of tetramethylammonium cations and alkali metal cations, especially sodium. ZSM-4 has a distinctive X-ray diffraction pattern which further identifies it from other known zeolites. The original alkali metal cations of ZSM-4 can be exchanged by ion exchange with other ions to form species of the zeolite which have exceptional catalytic properties especially in those hydrocarbon conversion reactions which do not involve any heat transfer.